Metallic seal

ABSTRACT

The present invention is directed to a resilient, annular, metallic seal member having a generally “j” shaped cross-section. The annular, metallic seal member includes a first end portion having a first distal end, a generally curled second end portion that extends to a second distal end, and a central body portion between and contiguous with the first and second end portions. The annular, metallic seal member has a first side and an opposite second side. The second end portion curls in a first direction in accordance with a predetermined radius such that the second distal end is located across from the first side of the annular, metallic seal member and the first and second distal ends do not face each other.

BACKGROUND OF THE INVENTION

The present invention relates to a metallic seal for the containment ofhigh pressure fluids, including gases, from cryogenic to highly elevatedtemperatures. More particularly, the present invention relates topressure-energized, annular metallic lip seals with lateral offset,angular and axial misalignment capability.

In the field of fluid containment of high pressure fluids, resilientmetallic seals are employed in applications where elastomeric andpolymeric materials cannot be used because of extremely high pressures,high temperatures and/or aggressive media. Such sealing devices areproduced in different configurations designed to meet a variety ofoperating requirements.

One such seal is the “Axial C-Seal”, show in FIGS. 1A and 1B, which wasdeveloped as an improvement in flexibility over the hollow metal o-ring.Like the metal o-ring, the axial c-seal may be used to seal gaps betweencylindrical surfaces, in mainly static application.

Other seals have been developed to perform this function, for example,those shown in the following U.S. Pat. Nos.: 4,457,523; 4,854,600;5,799,954; 6,257,594; and 6,446,978. All of these seals serve theirpurpose, but have limitations when required to be bothpressure-energized and capable of accommodating significantmisalignments of the cylindrical surfaces to be sealed.

In devices known as couplings, a rigid hollow proboscis or probe isinserted into a hollow receptacle in a fluid transmission system. Thereceptacle contains a sealing ring or multiple sealing rings, which aredilated by the inserted probe, thereby creating the required contactstresses to achieve fluid containment between the two bodies to besealed together.

C-seals are presently employed in couplings. Occasionally, due toimperfect field installation practices, the probe will be forced intothe receptacle before the centerlines or axes of the two components areproperly aligned. When this occurs, the probe may dent one side of thec-seal, which may not be sufficiently resilient to elastically deform,and therefore may leave a gap on the opposite side which results inleakage of fluid when the joint is pressurized.

It is highly desirable to provide an improved metallic seal whichovercomes the foregoing problems.

SUMMARY OF THE INVENTION

In accordance with the present invention it has now been found that ametallic seal has been provided which obtains the foregoing objectives.

The metallic seal of the present invention has a C-shaped portion whichconnects to a longitudinally extending portion. The c-shaped portiondesirably has a discrete radius with a smaller radius than the axialc-seal, to prevent contact between the probe and this relatively rigidarea during installation. The inside diameter of the c-shaped portion isdesirably extended axially towards the end of the c-shaped portion andtowards a first end of the seal, and slightly inwardly, desirablyterminating in a small inwardly curled portion forming a lip. Theopposed portion of the c-shaped portion connects to a longitudinallyextending portion which extends above or beyond the c-shaped portion andwhich desirably terminates in a small outwardly curved portion. Theoverall configuration of the seal is somewhat L-shaped, or J-shaped.

In a related aspect, the present invention is directed to an annularseal member having a generally “j” shaped cross-section and comprising afirst end portion having a first distal end, a generally curled secondend portion that extends to a second distal end, and a central bodyportion between and contiguous with the first and second end portions.The annular seal member has a first side and an opposite second side.The second end portion curls in a first direction in accordance with apredetermined radius such that the second distal end is located acrossfrom the first side of the seal member and the first and second distalends do not face each other.

In another aspect, the present invention is directed to an annular sealmember comprising a first side and an opposite second side, a generallyfrustoconical central body portion having opposite ends, a first endportion contiguous with one of the opposite ends of the generallyfrustro-conical central body portion, and a generally curled second endportion contiguous with the other of the opposite ends of the generallyfrustro-conical central body portion. The first end portion has a firstdistal end. The second end portion extends to a second distal end. Thesecond end portion curls in a first direction in accordance with apredetermined radius such that the second distal end is located acrossfrom the first side of the annular seal member and the first and seconddistal ends do not face each other.

In a further aspect, the present invention is directed to an annularseal member having a generally hook shaped cross-section, a first sideand a second opposite side. The annular seal member comprises a firstend portion having a first distal end, a generally curled second endportion that extends to a second distal end, and a central body portionbetween and contiguous with the first and second end portions. Thesecond portion curls in a first direction in accordance with apredetermined radius such that the second distal end is located acrossfrom the first side of the annular seal member and the first and seconddistal ends do not face each other.

In another aspect, the present invention is directed to an annularmetallic seal comprising a first side and an opposite second side, agenerally frustro-conical central body portion having opposite ends, afirst end portion contiguous with one of the opposite ends of thegenerally frustro-conical central body portion, and a curled second endportion contiguous with the other of the opposite ends of the generallyfrustro-conical central body portion. The first end portion has a firstdistal end. The second end portion extends to a second distal end. Thegenerally frustro-conical central body has a thickness that tapers inthe direction of the first distal and. The first distal end is slightlyegulated in a first direction. The second end portion curls in the firstdirection in accordance with a predetermined radius such that the seconddistal end is located across from the first side of the annular metallicseal and the first and second distal ends do not face each other.

Further features and advantages of the present invention will appearherein below.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will be more readily understandable from aconsideration of the accompanying drawings, wherein:

FIG. 1A is a side view, in longitudinal section, of a prior art axialc-seal;

FIG. 1B is a enlarged view of a portion of the view shown in FIG. 1A;

FIG. 2A is plan view of the annular seal member of the presentinvention;

FIG. 2B is a side view, in longitudinal section, taken along line 2B—2Bin FIG. 2A;

FIG. 2C is an enlarged view of the portion of the view shown in FIG. 2B;

FIG. 2D is a cross-sectional view of the seal of the present invention;

FIG. 2E is another plan view of the seal of the present invention;

FIG. 2F is a side view, in longitudinal section, taken along line 2F—2Fin FIG. 2E;

FIG. 2G is an enlarged view of a portion of the view shown in FIG. 2F;

FIG. 3 is a side view, in longitudinal section, of the seal of thepresent invention;

FIG. 4 is a schematic cross-sectional view of the installation of theseal of the present invention;

FIG. 5 is a schematic cross-sectional view of a seal of the presentinvention installed, with an axis of a probe displaced to the right;

FIG. 6 is a schematic cross-sectional view of installed seal of thepresent invention with the axis of the probe displaced to the left; and

FIG. 7 is a schematic cross-sectional view of an installed seal of thepresent invention at operating pressure.

DETAILED DESCRIPTION OF PREFERRED ENBODIMENTS

Referring now to the drawings in detail, FIGS. 1A and 1B show views of aprior art axial c-seal 10, showing an arcuate portion 12, outer sealingline 14 and inner sealing line 16.

Referring to FIGS. 2A–2G, there are shown various views of the seal 20of the present invention. Seal 20 comprises an arcuate portion 22, outersealing line 24 and inner sealing line 26. Seal 20 includes an inwardcurl 28 at one end of the arcuate portion which forms a return 29 at afirst edge 30 of seal 20, and the opposed end of the arcuate portionconnects to an inwardly tapering frustro-conical portion orlongitudinally extended portion 32 which terminates in an outward curvedportion 34 to the second opposed edge 36 of seal 20. The function of thereturn 29 is to provide stiffening and a lead-in which facilitatesassembly for the smooth insertion of the seal into an external cavityduring installation.

FIG. 2C is an enlarged view of the portion of the view of FIG. 2Bindicated by the dashed circle. Similarly, FIG. 2C is an enlarged viewof the portion of the view of FIG. 2F indicated by the dashed circle.

FIG. 3 shows a side view of a further embodiment of the presentinvention. Seal 40 comprises arcuate portion 42, an inwardly taperedtrustro-conical portion 44, inward curl 46 and outward curl 48. A firstportion 50 is connected to a second portion 52 of seal 40 bylongitudinally extending body portion 54, which depicts a preferredlongitudinally extending body of the seals of the present invention.Seal 40 further includes a material taper 56 at the frustro-conicalportion 44 wherein the thickness of the material forming seal 40decreases to increase flexibility of seal 40.

The preferred materials for the seals of the present invention includenickel super alloys and nickel cobalt alloys, although other metals maybe used.

The seal of the present invention has several significant advantages.One advantage is that the flexibility of the inward facing lip 29 isenhanced by increased distance from the more rigid c-shaped part of thesection and it can be deflected radially by a lower force.

Another advantage is that the configuration of the frustro-conicalportion 44 may be reshaped by deflecting relatively easily toaccommodate an off-center probe without plastic deformation of thisregion.

A further advantage is that the seal of the present invention may bemanufactured from a relatively thicker material stock in comparison tothe prior art axial-c-seal without an appreciable increase in insertionforce or galling tendencies.

Another advantage is that when the seal of the present invention ismanufactured from relatively thicker material, in comparison to theprior art axial c-seal, the greater material thickness and a closeproximity between the installed probe and the deflected innerfrustro-conical leg of the ring cross-section allow for higher operatingand proof pressures to he sustained without gross permanent deformation.

A further advantage of the seal of the present invention is enhancedreliability. Multiple insertions of the probe into prior art seals havebeen a problem for prior art seals.

Another advantage of the seal of the present invention results from thetapered cross-section of the frustro-conical portion. This flexiblefeature is advantageous for dynamic, sliding application, albeit at slowspeeds, because of reduction of contact stresses.

Referring to FIG. 4, there is illustrated the installation of a seal ofthe present invention showing the insertion of the aforesaid seal in thebody of a coupling. Seal 60 is installed in body 62 of a coupling, withretaining wall 64 positioned adjacent the seal and probe 66 spaced fromthe seal. Referring to FIG. 5, there is shown seal 70 in accordance withanother embodiment of the present invention. Seal 70 comprises anoutward curved portion 72 and frustro-conical portion 74. The seal 70 isinstalled in an interference relationship with body 62 and axialretaining wall 64, with probe 66 inserted in contacting, interferingrelationship with the seal adjacent to the frustro-conical portion 74.Elastic deflection of the seal inner lip and tapered frustro-conicalportion 74 permits lateral offset of the probe without leakage. The axisof probe 66 is displaced to the right vis-à-vis body 62. Referring toFIG. 6, there is shown a relationship similar to that shown in FIG. 5.However, the axis of the probe is displaced to the left vis-à-vis body62, widening the gap between body 62 and the frustro-conical portion 74.FIG. 7 is a view of an installed seal, similar to the view shown in FIG.5. However, FIG. 7 shows seal 60 at exemplicative high operatingpressure of 30,000 psi deflecting the walls of the seal wherein the seal60 is not completely deformed. The darker areas 80 on the body 62,retaining wall 64 and probe 66 show higher stress contact regions.

Naturally, variations in the seal are contemplated. For example, thelongitudinally extending portion could be conical or have a slightcurve. The c-shaped portion could have variations and flats and need notbe uniform. All shapes could be slightly irregular.

Various coatings, including silver or gold, may be beneficially appliedto the seal or its contact surfaces in order to improve its seilingefficiency. For dynamic applications, special anti-galling, low-frictioncoatings may be applied. Thus, sealing contact areas may be coated withsoft, lubricious and/or anti-galling materials.

It is to be understood that the invention is not limited to theillustrations described and shown herein, which are deemed to be merelyillustrative of the best modes of carrying out the invention, and whichare susceptible of modification of form, size, and arrangement of partsand details of operation. Rather, the invention is intended to encompassall such modifications which are within the spirit and scope as definedby the claims.

1. An annular axial metallic seal comprising: a first side and anopposite second side; a generally frustro-conical central body havingopposite ends; a first end portion contiguous with one of said oppositeends of said generally frustro-conica central body, said first endportion having a first distal end; said central body having a thicknessthat tapers in the direction of said first distal end; a generallycurled second end portion contiguous with the other of said oppositeends of said generally frustro-conical central body, said second endportion extending to a second distal end; said second end portioncurling in a first direction in accordance with a predetermined radiussuch that said second distal end is located across from said first sideof said annular axial seal and said first and second distal ends do notface each other and said first and second end portions and said centralbody being configured to provide said annular axial seal with a “j”shaped cross-section.
 2. The annular axial metallic seal according toclaim 1 wherein said annular axial metallic seal has a degree ofresiliency.